Refrigeration apparatus



Aug. 11, 1937.

W. G. MAYER l 3?.,090Af54V REFRIGERATION'APPARATUS 3 Sheets-Shag# 1WITNESSES Aug. 17, 1937.- w. G. MAYR ,(390,1454A REFRIGERATION APPARATUSmisa-nay 4. 41951 5 sheets-sheet 2 Aug. 17, 1937.

W. G. MAYER REFRIGERATION APPARATUS 5 'Sheets-Sheet 3 Filed May 4, 1 91` 'bananas n INVENTOR @n l1 adm/MVL WITNESSES .ZL/JM Patented Aug.17,1.9'37

PATENT OFFICE REFRIGERATION APPARATUS William G. Mayer,

Pittsburgh, Pa., assignor, by

mesne assignments, of one-half to Adico Development Corporation,

York,

poration of New New York, N. Y., a cor.. and one-half to InternationalCarbonio Engineering Company, Wilmington, Del., a corporation ofDelaware Application May 4, 1931, Serial No. 534,' 121 8 Claims.

This invention relates to the preservation of perishable materials, andmore particularly to the refrigeration of vehicles by means of solidcarbon dioxide.

Ordinary water ice as a refrigerant for vehicles,

such 4as trucks, carrying foodstuffs is not satisfactory, for variousreasons. Chief among these are the large bulk and welght of ice andbrine which must be carried, and the rather limited cooling effect andrefrigeration period available. Also, the refrigerating effect is quiterestricted.

The advantages of solid carbon dioxide, e. g., in the form of so-calledsnow or ice, are well known. Its temperature, is about -115 F., and

it does not melt, but sublimes. It thus provides greater refrigeratingpossibilities than water ice, and it eliminates the collection of liquidwith its attendant disadvantages. In general 1 pound of solid carbondioxide is capable of the same refrigerating effect as about pounds ofwater ice. Thus lower temperatures, with better preservation offoodstuffs, are possible, and pay loads and route lengths may beincreased. Furthermore, solid carbon dioxide does not require the brinesneeded with water ice, so that this source of non-pay weight, and thecorrosion due to brine, are eliminated.

These properties render solid carbon dioxide an ideal refrigerant,particularlyfor vehicular transportation of perishables. tially moreexpensive weight-for-weight than water ice; gaseous carbon dioxideformed on evaporation may exert an injurious effect on some gas with itsload, as Well as providing for temperature control. The constructions,whether vehicular or stationary, not achieved these ends satisfactorily.

It is among the objects of this n fvention toxprovide a refrigeratingunit for use with solid carbon dioxide which is compact, sturdy,eicient, affords maximum 'refrigerating eiect, in which the rate of heattransfer can be adjusted over a wide range, which eliminates contactofCO2 gas with the refrigerated materials, and utilizes the gas given offby evaporation -o f Ythe lsolid carbon difoxide i'.oaid intherefrigeration.: `Other objects land.mirentaseswill .appearhereinafter.

The apparatus provided by the invention com- However, it issubstanavailable'heretofore have now in use,

(Cl. (i2-91.5)

prises a suitable .refrigerator compartment in which there is disposed acontainer for solid carbon dioxide. Surfaces of the container areexposed to the compartment, and it is provided with means for increasingthe normal rate of heat transfer between the compartment and therefrigerant, which most suitably takes the form of a-base plate providedwith fins. Means are provided also for controllingthe rate of heattransfer, and thus the degree of refrigeration, which in the preferredembodiment Vincludes means for increasing or decreasing the radiatingarea of the solid CO2 relative to the compartment. The construction issuch that leakage of substantial 15 amounts of gaseous carbon dioxideinto the compartment is prevented, this gas being preferably led intothe insulated vwalls of the compartment Through these means Iaccompanying drawings, Fig.'1 is a fragmentary 2 side elevation of atruck having a refrigerated body compartment embodying the invention,

parts being broken away for clarity of illustration; Fig. 2 anenlargedperspective view of the carbon dioxide container shown in' Fig.l; Fig. 3 a perspective view of an insulating pad for use with thecontainer of Figs. 1 and 2; Fig. 4 a cross sectional View of thecompartment and unit shown in Figs. 1 and 2; Fig. 5 a plan View of theunit taken on line V-V, Fig. 4; and Fig. 6 a plan view of the cover ofthe unit.

Referring. to Figs. l to 6 a truck chassis -i is provided with a body A2having double Walls 2a' filled with suitable heat insulating material 3,such as the fibrous insulators now commonly used, for instance kapok orbalsa wool.

A container for solid carbon dioxide projects into the refrigerating`compartment thus formed, preferably through its top, as shown in Figs.l and 4, and in order to provide good heat transfer between itscontainer refrigerant and the compartment, the container is formed of ametal Vmensions are such as to provide for the insertion of theAstandard solid blocks of carbon dioxide l or multiples or uniformfractionsthereof.

'I'he container is preferably provided with means for increasing itsnormal heat radiating capacity, such as fins. Most suitably this isaccomplished by the use of a base plate provided with fins. Thepreferred embodiment, as shown in the drawings, comprises a metallicbase plate 5 connected to the side. walls and projecting laterallytherebeyond. Various types of heat conducting fins may be used, theembodiment shown comprising V-shaped fins formed by bending sheet metalto form corrugated strips 6. On the'upper side of base 5 these areconnected to the portions which extend beyond the container Walls, andare Welded to the latter. They also extend entirely across, and areconnected to,

the lower side of plate 5. This construction increases the heatconducting area, as compared with ordinary flat vand straight fins, andit-pro- Vides channels for circulation of air. Preferably base 5 andstrips 6 are provided with holes l. and slots 8 are cut in plate 5 andstrips 6, to increase the circulation of air over the side walls. Thisconstruction, with metallic connection between /the ns, side walls andbase, further enhances the heat transfer.

In order to render the container proof against leakage of 'CO2 gas intothe compartment, the

side walls and base are preferably welded to- The construction thusprovided is adapted to `eiiciently refrigerate the compartment, butbecause regulation of temperature is desirable, either to preventfreezing of the materials carried, or to keep them at a desiredtemperature,

and also to reduce CO2 consumption, means are provided for regulatingthe compartment temperature to a desired predeterminedvalue, byregulating the rate of heat transfer between the compartment and thesolid carbon dioxide.

In accordance with the invention temperature control is effected byvertical adjustment of the container, or of the CO2 refrigerant, orboth. As shown in Fig. 2, side plates 4 are provided with a plurality ofhorizontal rows of holes I0 for connecting the container to side walls 9of the hatchway by means of screws. ner the container may be adjusted inthe hatch- Way to ,-vary the vertical exposure x, Fig. 4, -of its sideWalls, thus increasing or decreasing the 5 refrigerating effect as needbe, both by altering the Aexposed heat conducting side wall area, and

by varying the relative are'a of solidCOz exposed to the compartmentthrough the container side walls. By the use of a plurality of rows Vofstag-l gered holes IG this adjustment is provided for, andleakage of gasbetween the container and hatchway walls is minimized. y f

Further control is afforded also by means of insulating pads placedunder the blocks I'I of solid carbon dioxide. Such pads reduce the rateof heat transfer through the base plate-by eliminating direct contactofthe blocks II with` plate 5. They also -reduce the area of CO2 exposedto the compartment through the side walls. A particularly suitableinsulating pad is shown inFig. 3. vIt comprises a hollow gas-tightboxlike structure I2 formed of metal, and to increase its strength thereis disposed Within it a cor-` rugated metallic reinforcing member I3.This adds strength while retaining the heat-insulat- InV this mani f,material, but is cork or thetlike,

justment.

the hatchway walls, this valve being adjustable `,to maintain thepressure at a desired predetermined` value, for example 5 to 15 pounds.This CO2 gas is quite cold, and while it may be relieved to theatmosphere, it is preferred to use it as an additional refrigerant.. Forthis purpose valve I8 opens into the insulation space between side walls2a, and circulates through insulation 3 surrounding, thus cooling thecompartment walls. In order to permit free circulation, the bodystructural lmembers I9 are provided with holes 20 as need be. The gasfinally escapes to the atmosengage catches I 'I on hatchway side walls9.

The containers may be of any desired size, depending upon the sizel ofthe compartment, the length ofhaul, and the degree of refrigerationneeded. They may be adapted to take a single, or a plurality of blocks,disposed horizontally, or stacked vertically.

Where the containers are to accommodate more than one block of carbondioxide, it is preferable to secure partition plates 2l therein to forman individual compartment for each block,

softl'iat as the blocks evaporate they will stay more or less in placeand not shift about.

In the use of the refrigerator unit thus provided the container isadjusted to provide an exposed vertical distance a: such as to maintainthe desired temperature in the compartment. This may be done whenassembling the vehicle, the builder knowing from the size of thecompartment and the container capacity what exposure to provide in orderto obtain any desired temperature. 'It has been found that, in general,l

five pounds per square' inch gas' pressure in the container issuiiicient to retard evaporation satisfactorily, and pressures up to 15pounds do not result in any appreciably greater retardation. In order toprevent extreme pressure within the chamber, should the valve fail tofunction, latches.

I6 are resilient enough to allow the gas to escape past gasket I5 afterit has reached a pressure of a few pounds above that for which the valveis set.

Solid carbon dioxide blocks are placed in the container, the cover isset in place, and the latches sprung under the catches, thereby tightlysealing the chamber. As evaporation of the CO2 proceeds to a point wherethe gaspressure within the chamber exceeds the pressure valve I8 is setfor,

Y the excess pressure is relieved through the valve and the gascirculates through insulation 3 about all parts of the walls, and stillfurther aids in. cooling the compartment.

In case insulation 3 is not a fibrous or loose valve I8 may open intothe outside atmosphere. Where meat or contributing furtherl and thelike, which are improved by carbon dioxide gas, are carried the valvemay open into the compartment to allow the gas to come into directcontact with such materials.

If it is desired to raise thetemperature in the compartment higher thanthat initially provided for, the 'container may be raised by removingthe screws from holes Ill and elevating it, or one or more pads of thetype described may be placed under the block to separate it from directcontact with the base radiation plate. By having a number of such padsof various thicknesses to select from, a wide range of temperaturecontrol will be made possible. Actual tests have shown that by varyingthevertical position of the container and by using insulating pads, atemperature range of between 40? F. below zero to 15 F. above can beobtained.

For large,vehicles, `and for lspecial purposes,`

any desired number of the units may beused, and they may be disposedotherwise than through the roof, where this appears to be desirable.construction described is preferred, however, be-

v cause the interior of the units are readily acces- Aprevent leakage ofvgaseous carbon dioxide into the compartment,

sible through the roof, the units do not interfere materially with theinsertion and removal of goods in the compartment when the units are inthis position, and because `warm air tends to rise to the roof.

The unit provided by `this invention requires but a small amount ofspace in a refrigeration compartment', as compared with water ice units,which results in providing more space for food; and larger pay loads.Furthermore, as the unit is relatively small, and is preferablyconstructed of a light metal, such as aluminum, lighter trucks can beused, which decreases the initial vehicle cost, and its upkeep, and alsoincreases the area of the district that can be served by a single .ve'

hicle.y As the container and radiation plate ,extend such a shortdistance into the refrigeration compartment, they interfere but littlewith eilicient packing of the latter with foodstuffs. By having'the gaspass into the insulation the carbon dioxide is made to serve twice,first by means of the radiation plate, and second by keeping the wallscold.

According to the provisions of the patent statutes, I have explained theprinciple and mode of operation of my invention and have illustrated anddescribed what I now consider to represent its `best embodiment.However, I desire to have it understood that, within the scope of theappended claims, the invention may be practiced otherwise than asspecifically illustrated and described.

I claim:

1. An apparatus for preservation of perishable materials comprising thecombination of arefrigerating compartment for said materials, a

1container for solid carbon dioxide refrigerant projecting downwardlythrough the compartment roof and having a base. and side walls of metalof high thermal conductivity connected to substantial amounts of meansfor maintaining gaseous carbon dioxide in the container under apredetermined pressure, said base having metallic heat conducting meansconnected thereto and extending laterally of the container walls, andmeans for adjusting said solid ycarbon dioxide vertically. of thecompartment to control the temperature of said materials by regulatingthe rate of heat transfer between the compartment and refrigerant.

The-

2. An apparatus for preservation of perishable I materials comprisingthe combination of a refrigerating compartment for said materialsprovided with a hatchway through the roof, a container for solid carbondioxide refrigerant pro-v jecting into said compartment through andver-y tically adjustable in said hatchway, said container having sidewalls and a base plate formed of metal of high heat conductivity andhaving Y its side Walls cooperating with the hatchway to tainer forsolid carbon dioxide refrigerant prov jecting into said compartmentthrough and vertically adjustable in said hatchway, said containerhaving side walls and a base plate formed v of metal of high'heatconductivity and having its side walls cooperating with the hatchway topreventleakage of r'substantial amounts of gase- -ous lcarbon dioxideinto the compartment, said base plate extending laterally beyond saidside walls and. being provided with corrugated metal plates formingopenchannelV-shaped heat-conducting fins, a removable closure for saidhatchway, said container retaining gaseous carbon dioxide gas underpressure in the container, and `a relief valve associated with saidcontainer for pressure.

maintaining said gas under a predetermined 4. `An apparatus forpreservation of perishable materials comprising the combination of arefrigerating compartment for said materials bounded by double heatinsulated walls and provided With a hatchway through the roof, acontainer for solid carbon dioxide refrigerant pro'- jecting'into saidcompartment through and vertically adjustable in said hatchway, saidcontainer having side walls and a base plate formed of metal of highheat conductivity and having its side walls cooperating with thehatchway to prevent leakage of substantial amounts of gaseous carbondioxide into the compartment, said base plate extending laterally beyondsaid side walls and being provided with corrugated metal plates formingopen channel V-shaped heat-conducting fins, a removable closure for saidhatchway, said container retaining gaseous carbon 'dioxide underpressure in the container, a relief valve connect-v ing'said containerwith the space between said double walls, means for' varying therelativearea of solid carbon dioxide exposed'fto the compartment throughthe walls to further regulate the temperature within said compartment,and means for increasing air circulation over said heatits side wallscooperating with the hatchway to l prevent leakage of substantialamounts of gaseous 5 forming open channel V-shaped heat-conductingthermal conductivity associated to prevent leak- 5 iinsa removableclosure for said hatchway, said age of substantial amounts of gaseouscarbon container retaining gaseous carbon'dioxide under dioxide into thecompartment, a removable gaspressure, and a relief valve associatedvwith said tight closure for the container for introduction containerwhereby to maintain said pressure at of solid carbon dioxide into thecontainer and 1() a predetermined point and adapted to'permit the formaintaining gaseous carbon dioxide therein 10 gas in excess of thepressure desired to escape under pressure, the base of said containerhavinto said double Walls in order to further cool ing on the sideexposed to said compartment l thecompartment, means-for insulating thesolid increased heat exchanging area. a relief Valve carbon dioxide fromthe container in order to associated with the container for maintainingfurther regulate the temperature Within said resaid gas under apredetermined pressure therein, 15

frigerating compartment, and means for increasand means for adjustingsaid solid carbon diing'air circulation over said heat-conducting ns.oxide vertically of the compartment to control l6. An apparatus for`preservation of perishable the temperature of said materials byregulating materials comprising the combination of a rethe rate of heattransfer between the compartfrigerating compartment for said materials,a ment and refrigerant. i 20 container for solid carbon dioxiderefrigerant 8. An apparatus for preservation of perishable projectingdownwardly into said compartment materials comprising the combination ofa refrom its roof, said container having side Walls frigeratingcompartment for said materials, a and a base plate formed of metal ofhigh heat f container for solid carbon dioxide refrigerant conductivityassociated to prevent leakage of projecting downwardly through thecompartment 25 Isubstantial amounts of gaseous carbon dioxide roof andadjustable vertically of the compartinto the'compartment, said baseplate being proment, the container having a base and side walls vided onthe side exposed lto said compartment of metal of high thermalconductivity connected with means providing increased heat exchanging toprevent leakage of, substantial amounts of surface, and one wall of thecontainer being progaseous carbon dioxide into the compartment, 30.vided with a removable gas-tight closure for inmeansfor maintaininggaseous carbon dioxide troduction of solid carbon dioxide into the coninthe container under a predetermined pressure, tainer'and for retentionof carbon dioxide gas said base having on the surface exposed to saidtherein, and means for adjusting said solid carcompartment increasedheat exchanging surface,

bon dioxide vertically of the compartment to and means for adjustingsaid solid carbon dioxide control the temperature of said materials byregvertically of the compartment to control the temulating the rate ofheat transfer between ,said perature of said materials by regulating therate compartment and refrigerant. of heat transfer between thecompartment and 7. An apparatus for preservation of perishablerefrigerant.

o materials comprising the combination of a refrig- WlLLIAM G. MAYER.`40

carbon dioxide into the compartment, said base plate extending laterallybeyond said side Walls and being provided with corrugated metal plateserating compartment for said materia1s,a con- CERTIFICATE 0F GORRECTIO.

tainer for solid carbon dioxide refrigerant assofprojecting downwardlytherein, the container having aV base and side walls of metal of highAugust-17, '1957.

cated with the roof of said compartment and l wILLIAu c, MYER.

Itis hereby .certified that error appears in thelprinted specificationofthe above nunbered patentorequiring correctionas follows: Page 2,second A colunm, line 51, strike out "engage catches 1Ton'hatchway'sidewa11s 9" and insert insteadthe syllable andwords pherethrough the cracks in the body walls; and that the said Letters Patentshould be read with this correction therein that the `same may conformto thev record of the case inthe Parana office.; o signes and sealedthis 19th day `or october, A. in. 1957. f

lHenry Van A rsdale (Seal) i Acting Commissioner of Patents.

, prevent leakage of substantial amounts of gaseous carbon dioxide intothe compartment, said base plate extending laterally beyond said sideWalls and being provided with corrugated metal plates eratingcompartment for said materia1s,a ccn- CERTIFICATE F GORRECTIO.

tainer for solid carbon dioxide refrigerant assofprojecting downwardlytherein, the container having aV base and side walls of metal of highAugust-17, '1957.

cated with the roof of said compartment and l 5 forming open channelV-shaped heat-conducting thermal conductivity associated to preventleak- 5 finsa removable closure for said hatchway, said age ofsubstantial amounts of gaseous carbon container retaining gaseouscarbon'dioxide under dioxide into the compartment, a removablegaspressure, and a relief valve associated vWith said tight closure forthe container for introduction container whereby to maintain saidpressure at of solid carbon dioxide into the container and 1() apredetermined point and adapted to'permit the for maintaining gaseouscarbon dioxide therein 10 gas in excess of the pressure desired toescape under pressure, the base of said container havinto said doubleWalls in order to further cool ing on the side exposed to saidcompartment l thecompartment, means-for insulating the solid increasedheat exchanging area. a relief Valve carbon dioxide from the containerin order to associated with the container for maintaining furtherregulate the temperature Within said resaid gas under a predeterminedpressure therein, 15

frigerating compartment, and means for increasand means for adjustingsaid solid carbon diing'air circulation over said heat-conducting ns.oxide vertically of the compartment to control l6. An apparatus for`preservation of perishable the temperature of said materials byregulating materials comprising the combination of a rethe rate of heattransfer between the compartfrigerating compartment for said materials,a ment and refrigerant. l 20 container for solid carbon dioxiderefrigerant 8. An apparatus for preservation of perishable projectingdownwardly into said compartment materials comprising the combination ofa. refrom its roof, said container having side Walls frigeratingcompartment for said materials, a and a base plate formed of metal ofhigh heat f container for solid carbon dioxide refrigerant conductivityassociated to prevent leakage of projecting downwardly through thecompartment 25 Isubstantial amounts of gaseous carbon dioxide roof andadjustable vertically of the compartinto the'compartment, said baseplate being proment, the container having a base and side walls vided onthe side exposed lto said compartment of metal of high thermalconductivity connected with means providing increased heat exchanging toprevent leakage of, substantial amounts of surface, and one wall of thecontainer being progaseous carbon dioxide into the compartment, 30

.vided with a removable gas-tight closure for inmeansfor maintaininggaseous carbon dioxide troduction of solid carbon dioxide into the coninthe container under a predetermined pressure, tainer'and for retentionof carbon dioxide gas said base having on the surface exposed to saidtherein, and means for adjusting said solid carcompartment increasedheat exchanging surface,

bon dioxide vertically of the compartment to and means for adjustingsaid solid carbon dioxide control the temperature of said materials byregvertically of the compartment to control the temulating the rate ofheat transfer between ,said perature of said materials by regulating therate compartment and refrigerant. of heat transfer between thecompartment and 7. An apparatus for preservation of perishablerefrigerant.

o materials comprising the combination of a refrig- WlLLIAM G. MAYER.`40

wILLIAu c.y MYER.

Itis hereby .certified that error appears in thelprinted specification.vof'the above nunbered patentrequiring Aeorrect'ionas follows: Page 2,second A colunm, line 51, strike out "engage catches 1Ton'hatchway'sidewa11s 9" and insert insteadthe syllable andwords pherethrough the cracks in the body walls; and that the said Letters Patentshould be read with this correction therein that the same may conform tothev record of the case inthe Patent offres.; a signes and sealed this19th day `or october, A. in. 1957. f

lHenry Van A rsdale (Seal) i Acting Commissioner of Patents.

